Stylus support for talking machines



Aug. 28, 1923.

, 1,466,555 H. HURM STYLUS SUPPORT FOR TALKING MACHINES Filed Aug. 9,1921 I Patented Aug. 28, i923;

enson i am, br .rnn s, rial-men. I

" STYLUS SUPPORT sea; TALxiNG ACHIN S Application filed A gust 9, "1921.Serial at. 490,998.

The subject ofthe invention is a stylus support for talking machii'ies,the principal characteristic of which is thatitis formed as a sort oflattice construction extending over the whole length of the support@This renders it possible forthe stylus support to be small in inertiayet suiiiciently'rigidto resist bending. Known stylus supports usually'are defective inthat they are not-sufficiently rigid, and thus easilybecome distorted, so that the delicate'vibrations of the stylus are nottransmitted to the diaphragm of the sound box with sufiicient accuracy.The stylus support of the invention is par-- ticularly intended for asound bo-x in which the stylus support is not rigidly connected with thediaphragm, but, in known'ma'nner, rests thereupon unconnected andtransmits by reason of its constant'contac't, the move- V I11 611i3' ofthestylus to the diaphragm. In]

. such case, it is necessary that the diaphragm be preliminarily'bentfrom its central posi tion for a certain degree by'the-stylus support,s'othat a certain tension exists between these two parts. This tensioncauses the two parts to remain in contact, no matter to which-side thevibration-takesplace. In accordance with the invention, this tension iscalculated of such size that the curveproduced is at least equal-to halfof the largest width of vibration which 'takes'place. With anunconnected stylus support, so' large a tension' assures an absolutely'correct transmission of movement and therewith a true reproduction ofthe sounds of tones. 1; Such an arrangement fulfills allrequireinentsasto the rigidity of the stylussupport'," which is due toits formation similar'to a truss or lattice support. In addition, theheight-of the lattice construction renders it possible in simplemanner-to provide as it will be shown hereafter a suitable point ofengagement for the spring, or the like, producing the tension. 7 a

The drawi 9 illustrates the subject of the invention in two forms ofcQnstruction.

Figs. 1 and 22 show a sound box with'the stylus support of the inventionin elevation andcross section. Figs. 3 and i are c0rresponding'illustrations of the other modification, which diifers'slightly with respect t'o the form and engagement of the spring. Inthe drawings a f The diaphragma which, according to Fig.

4has a fiat rigid center or according to Fig.

2 is shown arched'or curved, is arranged in known manner in thehousingbof the sound box and may be inserted therein 'by means of a ring-o ofresilient material. The end of the stylus support or bar 45," which inthe present case, is formed like a lattice support,

lies at the center of the diaphragm under a certain constant-pressure.It c'onsists suitably of a material which is oflow density, such as,duralumin, magnaluim, fibre or the like. By the latticed constructionover the entire length of the stylus bar I obtain a great rigidity andlightness, while at the same time preventing flexibility and excessiveinertia which would be the causes 'ofan incorrect transmission of therecorded sound waves.

' The part of the support, which serves for I the receptionof the stylusa, is provided with a perforation extending clear through,

so that it is possible to use a stylus of great length and to attach itin such manner that it may extend from the support'and respond to therequirements under which it -must operate; QT-he other end al of thestylus 'supportmay be provided with a simple point, by means of, whichthe support may be positioned, unconnected, but with a certain degree ofpressure, on the diaphragm; This pressure is so calculated that thedeformation caused thereby inthe position of rest of the diaphragm isgreater than the amount in which it will vibrate in one or the otherdirection, from itsposition of rest, in the operative position. 7 l

y Thelattice support is mounted with its edge facing the sound box inknown manner by means of I adjustable knife edges, or points, 5 In thepresent case two small pointed screws f are arranged in projections g ofthe sound box, the. points of which engage in suitable depressions of atransverse element h provided on the'support. To this trans verseelement is attached the end d of the support carrying the stylus, sothat the other end al is ad acent the center of the diaphragm a. Thespring lying substantially iio parallel to the diaphragm holds thestylus support to the sound box I), has a double action pressing it onthe one end against the adjustable point screw f, and on the other hand,by means of the above mentioned tension,. pressing it against thediaphragm. For this double purpose use is made of a hook (i which isconstructed at a point lying outside of the connecting line of the pointofmounting, this hook being simply formed by a cavity or depression. Theheight of the special stylusholder affords a special advantage when ompre to the usu l rod e' ylu holders as it dispenses with the necessity ofproviding a special projection for the pur- Po of h ing t e h od (Z3 Plae a a proper distance from the plane of the fulcrum point-s The saidhook engages the nd a pr g wh h, a th same. t me erts a pressure againstthe point screw 7", as ll as o y moveme on th a t ce suppo he spr g m ye a sp ra sp int which is provided at one end with a loop of wire orcord, or the like, by means of which it is hooked to the latticesupport. Thus it can be easily unhooked, and the stylus support and themembrane directly removed, if necessary. The other end of the springwhich, at is, is suitably stretched at the center, with respect to thetwo projections, thus remains permanently connected with the housing.The spring arrangement, not only permits of the convenient removal ofthe stylus support and the membrane, but also permits of any desiredpressure adjustment at the point (Z so that it is always possible toadjust said point on the stylus support accurately on the diaphragm toobtain the best effects. I The clearness and purity of the reproductionscan be controlled in simple manner at any time. 7

Having described my invention what I claim as new and desire to secureby Letters Patent, is 1-.-

1. In combination a diaphragm, a stylus supportarranged in front of saiddia- .p-hragm, said stylus support comprising a flat member presentingits edge toward said diaphragm, said flat member being relatively narrowat the top and wide at the bottom, a projecting element at the top ofsaid stylus support engaging said diaphragm, and a spring secured tosaid stylus support at the bottom for tensioning said projecting elementagainst said diaphragm,the force of said spring being directed in a linealmost perpendicular to the direction of oscillation of d s y pport henv bra ing, so at t mo me s f said s y u supp r are re is y a smallcomponen only of he en re o ce of sa d spr hs- .2- In, com in tion, aund box, ph gm upported n aid soun s said Witn ses.

sound box being provided with a fulcruming eme a tylu s pport e o prlihs e flat member presenting an edge toward said diaphragm and having atransverse base engaging said tulcruming element, said flat memher beingnarrow at the top and wide at the bottom, a point projecting from thetop into contact with the diaphragm, a spring secured at one end to thebottom of said flat member beyond the fulcruming element and secured atits other end to the sound box for maintaining said point in pressureengagement with said diaphragm.

3. A sound box adapted for use with tall;- ing'machinos, Said sound bog;having a central bore, a diaphragm stretched across said bore, a stylussupport consisting of a flat member triangular in shape and having atransverse element provided with depress sions on its upper face, pivotmembers on said sound box adap ed to rest in sa d dopressions, the upperend of the triangular suppor res ng aga n t th di phragm, a tensioningsp ng co nected to said sound X at one e d nd looped over h end of sa dgul r m mb r for ho ding he pivot memb s in' said dep ss ons and the endof the support against said diaphragm.

4. A sound box adapted for use with tall:- ing machines, said sound boxhaving a central bore, a diaphragm stretched across the e d of e bore,pivo mem e s ex nd ng downwardly from said sound box, a triangularstylus support having transverse members extending from either sidethereof, depressions in-upper side of said transverse member a ap d to ei e th ends of said piv m e s ylus suppo arrying a stylus, carrying atone corner a stylus, another corner restingv against the diaph gm o heso d b and the o her p o d d t a oo mem en te s on spring secured tosaid sound box and provided with a loop adapted to rest in said h k mmbe for d ng the s yl s suppor in c a t ith said iap agm and t t a v relement in co ct ith aid p ot embe s I combinati n, a sou d box,diaphragm mounted n. sa d s und bo a stylu bar pi e ne on end to s idsound box and h ving its ther end n ntact with said diaph agm, said s yls her ha i g a spring connected to stationary po nt. above the d aphragma d t the stylus bar a a p int fse f m he p ot,

t imo y whereof I ha e ereun o se my han i presence of two subscribinwitnesses.

J. E. MnNoHns, Gasser. Ross:

